Primitive streak

Primitive streak
Primitive Prim"i*tive, a. [L. primitivus, fr. primus the first: cf. F. primitif. See {Prime}, a.] 1. Of or pertaining to the beginning or origin, or to early times; original; primordial; primeval; first; as, primitive innocence; the primitive church. ``Our primitive great sire.'' --Milton. [1913 Webster]

2. Of or pertaining to a former time; old-fashioned; characterized by simplicity; as, a primitive style of dress. [1913 Webster]

3. Original; primary; radical; not derived; as, primitive verb in grammar. [1913 Webster]

{Primitive axes of co["o]rdinate} (Geom.), that system of axes to which the points of a magnitude are first referred, with reference to a second set or system, to which they are afterward referred.

{Primitive chord} (Mus.), that chord, the lowest note of which is of the same literal denomination as the fundamental base of the harmony; -- opposed to derivative. --Moore (Encyc. of Music).

{Primitive circle} (Spherical Projection), the circle cut from the sphere to be projected, by the primitive plane.

{Primitive colors} (Paint.), primary colors. See under {Color}.

{Primitive Fathers} (Eccl.), the acknowledged Christian writers who flourished before the Council of Nice, A. D. 325. --Shipley.

{Primitive groove} (Anat.), a depression or groove in the epiblast of the primitive streak. It is not connected with the medullary groove, which appears later and in front of it.

{Primitive plane} (Spherical Projection), the plane upon which the projections are made, generally coinciding with some principal circle of the sphere, as the equator or a meridian.

{Primitive rocks} (Geol.), primary rocks. See under {Primary}.

{Primitive sheath}. (Anat.) See {Neurilemma}.

{Primitive streak} or {Primitive trace} (Anat.), an opaque and thickened band where the mesoblast first appears in the vertebrate blastoderm. [1913 Webster]

Syn: First; original; radical; pristine; ancient; primeval; antiquated; old-fashioned. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • primitive streak — primitive streak. См. первичная полоска [у эмбриона]. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • primitive streak — n an elongated band of cells that forms along the axis of an embryo early in gastrulation by the movement of lateral cells toward the axis and that develops a groove along its midline through which cells move to the interior of the embryo to form …   Medical dictionary

  • Primitive streak — Infobox Embryology Name = Primitive streak Latin = GraySubject = 6 GrayPage = 47 Caption = Surface view of embryo of a rabbit. arg. Embryonic disk. pr. Primitive streak. Caption2 = Width = 215 System = CarnegieStage = 6b Days = 15 Precursor =… …   Wikipedia

  • primitive streak — Thickened streak of cells in early mammalian and avian embryos marks location of embryonic axis. Hensen&’s node is at the end of the primitive streak until the cellular movements of gastrulation cause it to regress caudally …   Dictionary of molecular biology

  • primitive streak — noun Date: 1854 an elongated band of cells that forms along the axis of a developing fertilized egg early in gastrulation and that is considered a forerunner of the neural tube and nervous system …   New Collegiate Dictionary

  • primitive streak — see germ band …   Dictionary of invertebrate zoology

  • primitive streak — noun Biology the earliest trace of the embryo in a fertilized ovum …   English new terms dictionary

  • primitive streak — the region of the embryo that proliferates rapidly, producing mesoderm cells that spread outwards between the layers of ectoderm and endoderm …   The new mediacal dictionary

  • primitive streak — noun : an opaque band that appears in the blastoderm in the axial line of the future embryo but somewhat behind the place where the embryo proper begins to develop and that represents a highly modified blastopore through which the involution of… …   Useful english dictionary

  • Полоска Первичная (Primitive Streak) — быстро разрастающийся участок ткани эмбриона, клетки которой, прорастая по обе стороны между наружной и внутренней пластинками зародышевого щитка и вперед по бокам от хорды, образуют мезодерму (ред.). Источник: Медицинский словарь …   Медицинские термины

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